Instrument Rating Checkride Practice Test

In a mountainous area with no published minimum altitude, what altitude must you maintain?

1. 1,000 feet above the highest obstacle

2. 2,000 feet above the highest obstacle

3. 4,000 feet above the highest obstacle

4. No specific altitude requirement

The correct answer is: 2,000 feet above the highest obstacle

In mountainous areas, maintaining a safe altitude above terrain is crucial for ensuring that pilots avoid potential obstacles. When there are no published minimum altitudes, the regulation requires pilots to maintain an altitude that is at least 2,000 feet above the highest obstacle within a horizontal distance of 4 nautical miles from the aircraft's intended flight path. This requirement helps ensure a margin of safety by providing sufficient vertical separation from the terrain and obstacles, which is especially important in the unpredictable terrain of mountainous regions where hazards may be obscured or not readily apparent. While the first option of 1,000 feet above the highest obstacle might seem reasonable in flat terrain or non-mountainous areas, it is insufficient in mountainous environments where obstacles can be significantly higher and close together. The other options suggest heights of 4,000 feet above the highest obstacle, which is more than necessary and could limit flight operations unnecessarily. Lastly, claiming no specific altitude requirement in such areas fails to prioritize safety, as the potential risks posed by terrain and obstacles are markedly higher in mountainous regions. Thus, keeping a buffer of 2,000 feet above the highest obstacle provides a standardized and safe approach to navigating these challenging environments.